Photographic silver-halide emulsions containing 1,3,4-triazaindolizine cyanine dyes



April 6, 194s.

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v N. HEIMBACH PHC '.I.OGRAPHICv SILVER-HALIDE EMULSIONS GONTAINING l, 5,4-TRIAZAINDOLI'ZINE CYANINE DYES l Original Filed April ll, 1946 5Sheets-Sheet 2A 36 40 44 fa-"Je .4K -sa .64 sa l April 6, 1948. NHEIMB'ACH 2,439,211() PHOTOGRAPHIC SILVER-HALIDE EMULSIONS CONTAINING l,5, 4-TRIAZAINDOLIZINE CYANINE DYES Original Filed April ll,`1946 3Sheets-Sheet 3 l IN VEN TOR. NEW'V #HMB/4CH BYD Patented Apr. 6, 1948Unirse stares .erreur oFFlCE PHOTOGRAPHIC SILVER-HALIDE EMUL- SIONSCONTAINING 1,3,4-TRIAZAIN- DLIZINE CYANINE DYES Newton Heimbach,Binghamton, N. Y., assignor to General Aniline & Film Corporation, New-York, N. Y., a corporation of Delaware e @riginal application April;11, 1946, Serial No. 661,353. Divided and this application June 7, 1946,Serial No. 675,289

This invention relates to photographic gelatino-silver-halideemulsionsand more particularly to photographic emulsions sensitized bymeans of new asymmetrical dyes of the 1,3,4

triazaindolizine type.

In the preparation of cyanine sensitizing dyes, a large variety ofheterocyclic bases have been used in the formof their quaternary saltsto obtain dyestuffs with varying degrees of sensitizing activity andsensitiz-ing ranges. A Wide choice of symmetrical and asymmetrical dyesis 4 Claims.

possible by a suitable choice of intermediates.

Moreover, similar bases are used in combination with a variety ofheterocyclic compounds containing active methylene groups to producemerocyanine dyes.

The quaternary Vdyestuifs obtained from nonquaternarynitrogen-containing heterocyclic bases such as thiazoles, oxazoles,selenazoles, quinaldines and the like; for `,the most` part, have eX-tremely lovv Water solubility and, accordingly,

are not always readily removed from the photographic layers in aqueousprocessing baths.

The residual dye` stain is particularly undesira-.,u

ble in photographic lms and papers. Moreover, it may frequently bedesirable to use such dyes as screening or filter layers, in which caselarge concentrations of the dyesare necessary. Such applications areoften limited by the difficulty of removal of dyestui from the layerduring the processing operations because of low Water solubility.

Previous proposalsto obtain dyestuifs of suitable Water solubility Werelargely dependent upon` a choice of the particular quaternary salt used.For example, acid groups `such as a-halogen acetic acids have beenintroduced during quaternation to increase solubility.

An object of the present invention is to prol vide photographicsilver-halide emulsions with sensitizing dyestuffs containing a1,3,4-triazaindolizine nucleus.

A further object is to provide such dyes which are added to photographicsilver-halide emulsions or coated thereon as an overcoating, Whereby thesensitivity of the emulsion is increased.

A still further object is to provide photo-sensitizing dyestuls havingappreciable Water solubility and readily removed from the exposedemulsion layer during processing.

`carbalkoxy, e. carbpropoxy and the like, aryl, e. g., phenyl,

" Other objects Will appear hereinafter.

I have discovered that the bases of 1,3,.4-trlazaindolizine give rise toseveral different series of cyanine dyes, all of which are excellentsensitizers for photographic emulsions. The bases, which are numbered inaccordance` with Beilstein and accepted usage, have the followinggeneral formula:

wherein R1 represents an alkyl group, e. g., methyl or ethyl, R2represents hydrogen, alkyl, e. g., methyl, ethyl, propyl, butyl, and thelike, g., carbmethoxy, carbethoxy,

tolyl, phenethyl, naphthyl, dphenyl and the like, and R3 and R4represent hydrogen, alkyl and aryl as in R2, aralkyl, e. g.,ibenzyl,methyl benzyl, ethyl benzyl, etc., alkoxyphenyl, e. g., methoxyphenyl,ethoxyphenyl, propoxyphenyl and the like, dialkoxyphenyl, e. g.,dimethoxyphenyl, diethoxyphenyl, dipropoxyphenyl, and the like.

The compounds numbered from 1 to 6, 9 to 14, and 16 to 22 are preparedbyheating a 3-amino- 1,2,4-triazole with an appropriate -diketone inabsolute alcohol in the presence ci a small quantity of an organic basesuch as triethylamine or piperidine. The actual method employed in thisi (1s) ein? -methyM-[2,41dlmethoxyphenylld,Aftriazaindoilzine (21) O CH:

22) ein l )en @Brr EN.

with any or the known cyolammonium qua-ternary cyanine dye saltintermediates containing a reactive group.

The iiyestufis derived from the alkyl or aralityl Quaternary salts ofLmftriazaindolzines and ey- 2@ .clammonium `Cluateruary oyanine dye saltinter mediates have the lollowine general formulae:

phenethyl, and the like, R2, R3 and R4 have the same values as givenabove, R5 is either hydrogen, alkyl, e. g., methyl, ethyl, propyl,butyl, and the like, Re is either hydrogen, or a methyl group, Xrepresents an anionie, acid radical, e. g., C1, Br, I, C1634, SOsCI-Is,SOrCzI-Is, SOaCsH4CI-I3 and the like, Z represents the atoms necessaryto complete a nitrogenous heterocyclic system of the type usual incyanine dyeslsuch, as pyridine, lepidine, quinoline, Lndoline, pzgazole,thiazoline, thiazole, thodiazole, selenazole, selenazoline, oxazoline,benzothiazole, benzoselenazole, benzoxazole, naphthothiazole,naphthoselenazole, and the like, and n represents a positive integerranging from l to 2.

In the preparation of these new dyestuis, the 1,3,4-triazaindolizineAbases are converted into their corresponding alkyl or aralkylQuaternary cyclammonlum salts in the manner usual for the conversion ofother nitrogenous heterocyclic bases to the quaternary salt form, l. e.,by fusion with an alkyl or aralkyl halide, or by heating the, ,base`with an alkyl or aralkyl halide in a sealed tube in a Water-bath underincreased pressure; A molecular equivalent of the Quaternary salt thusobtained is heated with a molecular equivalent of the cyclammoniumquaternary cyanine dye salt intermediate in the presence of a condensingagent such as ia heterocyclio nitrogenous base or an alcoholv"containing a small quantity of a tertiary base at reflux temperature.

As condensing agents employed in the preparation of the new dyes of thepresent invention, the following may be advantageously employed:heterccyclic nitrogenous bases such as pyridine, methyl pyridine,dimethyl pyridine, ethyl pyridine, ethylmethyl pyridine, trimethylpyridine, quinoline and the like, or an alcohol such as methyl, ethyl,propyl, isopropyl, butyl, isobutyl and the like inV thepresence of abasic tertiary catalyst such as trimethylamine, triethylamine, and thelike. In general, the amount of condensing agent used may vary withinwide limits, e. g., from 1 to 25 mols. Concentrations ranging from 1 molto about 15 mols are preferred, however.

The following examples describe in detail the methods for accomplishingthe above objects, but it is to be understood that they are insertedmerely for the purpose of illustration and are not to be construed aslimiting the scope of the invention.

Eamplel CHO H N-N a o-omoHa): 1-

\ GH: :N

N :Ha l

3.45 grams of 2-isopropyl-5-methyl-7-methyl- 1,3,4-triazaindolizineethiodide, 2.34 grams of 2- methyl-mercapto-G methoxy quinaldineethiodide, 2 cc. of triethylamine and 15 cc. of isopropyl alcoholarereuxed for one hour. Upon cooling, the dye precipitates. The iinalproduct is ltered and recrystallized from ethanol. The dye sensitized asilver-bromoiodide emulsion to 585 ma, with a maximum at 535 me.

dolizine ethiodide, 0.39 gram of 2-(-ethy1-- 2.06 grams of5-ethyl-7-(4-methoxyphenyl) fi f and the solution heated at: reflux forabout 1A hour. 10 cc. of'piperidine are then added and the reactionmixture heated for about 10 minutes. The reaction mixture is cooled, theprecipitate Vrecovered and. recrystallized from ethanol. The dyesensitized a silver-bromoiodide emulsion to about 590 ma, with a maximumat 540 ma.

3.65 grams of 5-methyl-7-phenyl-1,3,4-triazaindolizine ethiodide and3.04 grams of Z--acetanilidovinyl benzothiazole ethiodide are reiluxedin 15 cc. of dry pyridine for 40 minutes. Ethyl alcohol is added to thecooled reaction mixture, and after several hours of standing, the dyecrystals are ltered and recrystallized from ethanol. The dye sensitizeda silver-bromoiodide emulsion to 640 mit. with a maximum at 610 mit.

0.45 gram of 5-methyl-7-pheny1-1,3,4-triazainmethylmercaptovinyl)-6-methoxy benzothiazole ethiodide, 15 cc. of isopropyl alcohol and 0.2ec.`

Example V 3.79 grams of vZ-'phenyl-j?dimethyl-1,3,e1=tri azaindolizineethiodide, 3.92 grams of 2-(4.- ethoxy-L-butadienyl)-benzothiazoleethiodide, and 15 cc. of dry pyridine are reuxed for 50 minutes. Ethylalcohol is added to the cooled re- CzHa action mixture, and afterseveral hours of standing, the dye crystals are ltered andrecrystallized from ethanol. The dye sensitized a silver-bromoiodideemulsion to 760 me, with a maximum at 720 my.

Example VI CjHs tized a `silver--bromoiodide emulsion to 720 me,

with a maximum at 680 mu.

3 Example VII S HaC/ I CO 3.79 grams of5-methyl7p-toly1-j1,3,4-triazaindolizine ethiodide and 3.97 grams of2-(6- anilino-1,3,5-hexatrieny1) thiazoline methiodide are mixedtogether in 8 cc. of dry pyridine. The resulting mixture is gentlyboiled, under reflux, l for about 40 minutes. The reaction mix-ture is`75 'the 'accompanying drawing illustrate the regions 10 thenchilled andthe crystalline Adye Whih estrates Quit is filtered and relystallilzed@fram methanql. The `dye sensitized a silver-brom@- iodide emulsion to7.60 .mit with a maximum .at

3.17 grams of 2,5,7trimethyl-1,3,4-triazainclolizine ethiodide, 4.48grams of 2-(6-anilino- 4-ethy1-1,3,5-hexatrienyl) benzothiazoleethiodide, and 12 cc. of dry pyridine are refluxed for 1 hour. Ethylalcohol is added to the cooled reaction mixture and after several hoursof standing, the dye Acrystals are filtered and reerystallized -fromethanol. The `dye `sensitized a silverbromoiodide emulsion to `890 mp.,with a. maximum at 760 my.

Exampie VIII was Yrepeated with fthe exception lthat 3.30 lgrams `of,7diethyl1,3,4f1triazaindolizine ethiodide was substituted for 3.117grams of 2,5,7 trimethyl-1,3,4-triazaindolizine ethiodide. The dyesensitized a silver-'bromoiodide `emulsion -to'79'021-nu, with -amaximum at 750 ma.

' The :diagrammatic speotrograims constituting ofthespectrum to whichthe various 1,3,4-tri- "azaindolizine cyanine dyes will sensitize agelatinov silver-'halide emulsion containing about Li-% of silver-halideand the extent of the sensiltization at various wave lengths. The nineg- Vwith the preceding examples.

In the preparation of photographic gelatinesilver-developing-outemulsions, such as, gelatino-silver-chloride, gelatino silverchlorobromide, gelatino-silver-bromoiodide emulsions, and the like,containing the monoand Polymethine dyestuis of the present invention, itis only necessary to disperse the dyestuffs inthe emulsions. It isconvenient to add the compounds from solutions in appropriate solvents.An alcohol, such as methanol or ethanol, is satisfactory, as a solventfor the dyestuls.

Emulsons prepared in accordance with this invention can be coated in theusual manner upon any desired support, such as cellulose nitrate,cellulose acetate, polyvinyl acetal resin, glass, paper and the like.

The concentration of these new dyestuis in IA the emulsion can varyWidely, i. e., from about 5to about 100 mg. per liter of flowableemulsions. 'Irhe concentration of the dyestuE will vary according to thetype of light-sensitive material inl the emulsion and according to theeffect desired. The suitable and most economical concentration forany-given emulsion will be apparent to those 'skilled in the art uponmaking the ordinary tests .This is due primarily to the increased watersolubility imparted to the dyestuis by the presence therein of the1,3,4-triazaindolizine nucleus.

This application is a division of my copendingl application, Serial No,661,353, filed April 1 1, 1946. 4

While the present invention has been described in considerable detailwith respect to certain preferred procedures, materials and uses, it isunderstood that the new Class of mono'- and polymethine1,3,4-triazaindolizine cyanines and their use as sensitizing dyes is notlimited thereto, and that numerous variations and modifications may bemade. As for example, by condensing a quaternary salt of a1,3,4-triazaindolizine with a dialkylaminobenzene in the presence of abasic 4condensing agent, e. g., piperidine, styryl dyes are obtained.The scope of the invention is to be limited solely by the appendedclaims.

I claim: 1.' A photographic gelatino silver-halide emulsion whichcontains a dyestui characterized by a formula selected from the classconsisting cf the following formulae:

wherein R represents a member `selected from the class consisting ofalkyl and aralkyl groups, R2 is a member selected from the classconsisting of hydrogen, alkyl, carbalkoXm, and aryl groups, R3 and R4represent the members selected from the class consisting of hydrogen,alkyl, aryl, aralkyl, alkoxyphenyl, and f dialkoxyphenyl groups, R5 is amember selected from the class consisting of hydrogen and alkyl groups,Re is a member selected from the class consisting of hydrogen and methylgroups, n represents a positive integer ranging from 1 to 2, Xrepresents an anionic radical, and Z represents the atoms necessary tocomplete a heterocyclic nitrogenous system.

2. A photographic gelatino silver-halide emulsion which contains adyestuff of the following structure:

CH: ma

4. A photographic gelatine silver-halideemul- 13 14 sion which containsa dyestuff of the following v structure:

Ho \NN l o-oH=oH-cH=oH-CH= =N NEWTON I-IEIMBACI-I. UNITED STATES PATENTSREFERENCES CITED 15 Number Name Date 2,153,928 Kendall Apr. 11. 1939 Thefollowing references are of record in the le of this patent: v

